Bon jour f,
I don't know that I can really tell you anything you don't already know. It doesn't surprise me that your Civic was stolen. They're always on the Top 10 list of most popular cars among car thieves.
Ditto for your stereo. If you put in a fancy system, you're just asking for somebody to steal it. Sorry for sounding so cynical, but it's something I would never do, for that very reason. Nobody wants my AC Delco stock radio in my Chevy, so it never causes me any worries.
If your insurance company doesn't consider your car a high risk, I wouldn't worry too much about it (although I'm nervous about parking any car without a garage). It's not like your car is going to be on high priority on the order list for the car thieves. There aren't that many recipients for your "donor" parts.
Yes we hear all the Montreal car-theft stories around here. I can't count the number of times a wrecker has said to me "no we don't have those parts in stock, but I can put it over the radio to Quebec and you'll probably have your parts in a couple of days." Of course, they always say this jokingly, and I've never taken them up on their offers, but they do usually add that if I want to specify a colour, the odds are REALLY good that I can get a perfect match. wink
Still, if you're really worried, you can always contact the Montreal Alfa Owners' chapter for their advice. Toronto's a bit different than Montreal, so maybe my opinions are worthless. wink
BTW welcome to the board.